In the field of the packaging of products, particularly food products, materials are known which are composed of superimposed layers which are mutually connected in order to meet the need to protect and/or preserve the products and the need to achieve an aesthetically valid presentation of the packaged product.
Such materials are generally composed of at least one layer made of cellulose material, such as paper or the like, which is intended to constitute the visible layer of the package, and at least one layer made of synthetic material, which is intended to make contact with the product. The cellulose layer makes it possible to obtain a natural visual and tactile presentation, which is highly appreciated in the food sector, while the synthetic layer or layers adequately isolate the product from the outside environment, preserving it against contaminations and avoiding its outward release.
Moreover, the cellulose layer can be printed with the most disparate techniques in order to achieve an adequate presentation of the product and provide useful information to the customer.
The field of food product packaging uses compound materials in which the layer or layers made of synthetic material are stably anchored to the cellulose layer such that the two layers are integral therebetween. Such compound materials have the advantage that they can be used without problems in automated production lines for packages, bags, envelopes, containers or the like, since the various layers of the compound material remain tightly coupled to each other during the traction of the material along the line even in the presence of intense stresses. On the other hand, these compound materials have problems that are not easy to solve when they must be disposed, if a separate disposal of the cellulose layer with respect to the synthetic layer or layers is required. These materials can be disposed separately only by means of complicated and expensive systems which very often are not economically convenient. For this reason, compound materials of this kind are generally disposed in a non-separated manner by sending them to landfills or incinerators.
Substantially, the materials composed of superimposed layers that are currently used, particularly in the field of packaging food products, are unable to combine in a fully satisfactory way the need to have an adhesion between the layers that compose them that is sufficient to allow their use without problems in automated lines for the production of packages, bags, envelopes, containers or the like with the need to be able to perform in a simple manner a separate disposal of the layers that compose them.